title: A new allele of Lyl1 confirms its important role in hematopoietic stem cell function.
abstract: Lyl1 codes for a bHLH protein that is an important regulator of hematopoietic stem cell function. An existing mutant allele of Lyl1 features a lacZ gene inserted in-frame into the fourth exon, leaving behind the N-terminus and the DNA-binding basic region, resulting in a translated chimeric protein. Here, we have generated a null allele, which allowed us to examine residual function of the N-terminus in the absence of a bHLH region. The new Lyl1-/- mouse model exhibited a reduced ability to generate lymphoid lineages and a somewhat more severe hematopoietic repopulation defect when transplanting purified hematopoietic stem cells. Our data show that in the absence of the HLH but presence of the N-terminus, residual function of the Lyl1 is detectable but relatively minor. The new model may be of use for studies of Lyl1 in which a null allele is required, or for which presence of the LacZ may complicate the combined use of additional mouse models bearing the lacZ marker.
authors.affiliation: Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: George P
authors.initials: GP
authors.lastname: Souroullas
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Goodell
mesh_terms: D000483:Alleles; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000502:physiology*; D001772:Blood Cell Count; D015139:Blotting, Southern; D016026:Bone Marrow Transplantation; D017931:DNA Primers / Q000235:genetics; D005434:Flow Cytometry; D005838:Genotype; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout / Q000235:genetics; D023421:Models, Animal; D009363:Neoplasm Proteins / Q000235:genetics* / Q000502:physiology*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D017931:DNA Primers; D009363:Neoplasm Proteins; C490130:Lyl1 protein, mouse